msf > load [plugin name]: The load command loads a plugin from Metasploit's plugin directory. Arguments are passed as key=val on the shell. For example, load pcap_log.
msf > unload [plugin name]: The unload command unloads a previously loaded plugin and removes any extended commands. For example, unload pcap_log.
msf > loadpath [module path]: The loadpath command will load a third-party module tree for the path so you can point Metasploit at your 0-day exploits, encoders, payloads, and so on. For example, loadpath exploit/windows/test/test_module.
msf > connect [IP]: This is similar to netcat. It is good for banner grabbing and interacting with the service. For example, connect 192.168.1.10.